#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	int n = 0;
	int m = 0;
	int i = 0;
	int num = 1;
	scanf("%d %d", &n, &m);
	i = n - m + 1;
	while (n>=i)
	{
		num *= n;
		n--;
	}
	printf("%d", num);
	return 0;
}